Auth0 vs Keycloak
Two sides of the authentication decision: hosted service and open-source service. When each fits, what it costs, who moves from one to the other, and what makers who chose it say.
Which fits you
Choose Auth0 if- You sell to companies whose IT team will ask for SAML SSO or SCIM
Use it whenA customer's security review asks for certifications and identity features a younger provider can't show.
Trade-offHeavier to configure and pricier than newer options for a solo project.
Choose Keycloak if- A self-hosted identity server with SSO, OpenID Connect, SAML and user federation for several apps at once.
Use it whenYou must keep identity on your own servers, or several internal and customer apps should share one login.
Trade-offA heavy Java server to run, upgrade and theme; more admin console than a small app usually needs.
At a glance
| Auth0 | Keycloak | |
|---|---|---|
| Used by | 21 makers' products · 17 open-source projects | 3 makers' products · 16 open-source projects |
| Cost at default usagemonthly active users 10k MAU | $0/mo Free | — |
| Downloads | 1.8M/wk−25% vs npm | 986.9k/wk−48% vs npm |
| Pricing | Free tier; paid plans priced by active users and features. · paid from $35/mo | Free (open source). |
| Free tier | Yes | Yes |
| Open source | No | Yes · self-hostable |
Cost as you grow
Both cost $0 up to 25k MAU; from 50k MAU Keycloak costs less ($0 vs $3,500). They're different kinds of tool — hosted service and open-source service — so the prices don't buy the same thing.
The numbers, plan by plan
| Monthly active users | Auth0 | Keycloak |
|---|---|---|
| 100 | $0 Free | $0 Self-hosted (open source) |
| 1,000 | $0 Free | $0 Self-hosted (open source) |
| 5,000 | $0 Free | $0 Self-hosted (open source) |
| 10,000 | $0 Free | $0 Self-hosted (open source) |
| 25,000 | $0 Free | $0 Self-hosted (open source) |
| 50,000 | $3,500 Essentials | $0 Self-hosted (open source) |
| 100,000 | over plan limits | $0 Self-hosted (open source) |
| 250,000 | over plan limits | $0 Self-hosted (open source) |
| 1,000,000 | over plan limits | $0 Self-hosted (open source) |
What makers say
Makers on using it for authentication, from Product Hunt and Starter Story interviews, each linked to the source. Products with a page of their own and fuller notes first.
On Auth0A huge thanks to Auth0 for helping us out with the authentication flow. They were really quick with the onboarding process and even with the support tickets.
For handling our user authentication with enterprise-grade security, so our users can log in instantly and focus on their data.
I had a simple login system using Auth0 and it would unlock access to the premium content on the website.
On KeycloakKeycloak is the class leader in Oauth, and it powers our single single for OIDC.
Loved and watch-outs
Themes that recur in makers' words and Hacker News comments, each linked to what it summarises.
Auth0KeycloakOn Product Hunt: 5.0★, 5 reviewsWho uses each
Auth021 makers' products
Ada.im
Chronicle
DGi
EddyOwl
Enhance-d
SeyftAI
WaydevKeycloak3 makers' productsWhat makers pair each with
With Auth0
Chronicle
Cypress
Svix
bring.order2chaosWith Keycloak
Directus
RefineNeither quite right?
See the whole authentication decision →
ClerkHosted serviceDropping prebuilt sign-in, profile and organization UI into a React or Next.js app.vs Auth0 →
SupabaseBundled with your backendApps already on Supabase — auth is part of the same project as the database.vs Auth0 →
FirebaseBundled with your backendMobile and client-heavy apps already using Firebase.
Better AuthLibrary in your appTypeScript apps that want users and sessions in their own database, at no cost.vs Auth0 →
WorkOS